The present invention relates to novel adenosine derivatives, pharmaceutically acceptable salts thereof and pharmaceutical compositions containing them as an active ingredient.
Hypertension is one of the most serious risk factors causing cerebral apoplexy and cardiopathy which are included in the major causes of death. The frequency of hypertension is increasing as the population becomes older, and it is estimated that about 20% persons of the total population in Japan are suffering from hypertension. Thus various antihypertensive agents such as diuretics, sympathetic depressant drugs, direct-acting vasodilators, calcium antagonists or angiotensin antagonists have been developed and used for a treatment of hypertension. However, for example, side effects such as bradycardia causing various symptoms such as tiredness, depression of activity, disturbance of cerebral circulation or cerebral ischemia are sometimes observed under the treatment with sympathetic depressant drugs. Therefore, the developments of antihypertensive agents having greater safety and effectiveness are desired. As a result of investigations for orally administrable antihypertensive compounds, the inventors have found adenosine derivatives having vasodilatively hypotensive effect as well as low toxicity and good safety.
An object of the present invention is to provide new adenosine derivative and pharmaceutically acceptable salts thereof having an excellent antihypertensive effect. Another object of the present invention is to provide pharmaceutical compositions containing these adenosine derivatives or pharmaceutically acceptable salts thereof as an active ingredient.